The present invention concerns phosphonopolyester oligomers and reaction products thereof.
Phosphorus-containing materials are well known as fire retardant agents in polymers such as polyester resins, polyurethane resins, epoxy resins and the like, particularly when employed in combination with a halogen such as chlorine or particularly bromine.
The present invention provides a method for incorporating phosphorus into the polymer chain of such resins and in certain instances the oligomers of the present invention contain chlorine or bromine in addition to phosphorus, in which instance a method for incorporating both phosphorus and a halogen into the polymer chain of the resins is provided.